content: /*
   * The MIT License (MIT)
   *
   * Copyright (c) 2016 Dmitry Ivanov
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  package io.dmitryivanov.crdt;
  
  import io.dmitryivanov.crdt.helpers.Operations;
  
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  
  public class GSet<E> {
  
      private Set<E> set;
  
      public GSet() {
          set = new HashSet<>();
      }
  
      GSet(Set<E> set) {
          this.set = new HashSet<>(set);
      }
  
      public void add(final E elem) {
          set.add(elem);
      }
  
      public Set<E> lookup() {
          return Collections.unmodifiableSet(set);
      }
  
      public GSet<E> merge(GSet<E> anotherGSet) {
          final HashSet<E> newSet = new HashSet<>(set);
          newSet.addAll(anotherGSet.getSet());
          return new GSet<>(newSet);
      }
  
      public GSet<E> diff(GSet<E> anotherGSet) {
          return new GSet<>(Operations.diff(set, anotherGSet.lookup()));
      }
  
      // Visible for testing
      Set<E> getSet() {
          return set;
      }
  
      @Override
      public boolean equals(Object o) {
          if (this == o) return true;
          if (o == null || getClass() != o.getClass()) return false;
  
          GSet<?> gSet = (GSet<?>) o;
  
          return set.equals(gSet.set);
  
      }
  
      @Override
      public int hashCode() {
          return set.hashCode();
      }
  }
  